Reaction of coal and ammonia to make hydrogen cyanide



United States Patent Ofice 3,501,267 Patented Mar. 17, 1970 6,501,267 REACTION OF COAL AND AMMONIA TO MAKE HYDROGEN CYANIDE Glenn E. Johnson, Pittsburgh, Albert J. Forney, Coracoal is heated to a temperature of from about 1000 C. to about 1300 C. Heating is accomplished by any known manner such as, for example, by electrical resistance means or by a furnace. In the heating zone, the coal is maintained as a fixed, fluidized or moving bed, or it can opolis and William A. Decker, Pittsburgh, Pa., as- 5 sages s-fl p as 22.525212021 523 1: asssglszaazahssi y e ecre ary o e 11 error N0 Drawing Filed 13 19 3, s 712,59 coal particles to fall substantially freely through the zone. Int. Cl. C01c 3/02; C01b 1/02 HCN-containing gases are produced by the ammoniated US. Cl. 23151 6 Claims coal-ammonia reaction, and can be removed from the heating zone by means of a pump or an inert carrier gas. Likewise, unreacted ammonia gas or unreacted ammonia ABSTRACT OF THE DISC O decomposition products (hydrogen and nitrogen) or un- Hydmgen cyanide is produced by reacting ammoniated reacted gases released by the coal can serye as carrier gas. coal with ammonia at temperatures of about 1000 to The mam P P of an eflefllally PP camel gas 15 13000 to move the coal more rapidly through the reactor so as to prevent the char and solid particles from sticking to the reactor surfaces which could cause plugging in a small This m whlch relates to the producuon of hyunit. Unreacted gases present during the reaction are suffidrogen cyanide from coal, resulted from work done by the cient to prevent plugcing in large units Bureau of Mmffs the eparlmerit 9 the Intenor Removed product gases of the reaction are then treated and the domestic title to the lnvention 1s 1n the Governwith a c onv enti on all commercial process to remove the ment' HCN. For example, the product gas can be washed with Hydiogen cyzimde (hydmcyamc acld) IS an ImPPrtant dilute H 50, to remove unreacted NH then washed with industrial chem1ca1 compound used, for example, in the 25 Watr to adsorb the HCN pmducuon of dyes chelates Pi and acrylommles' Since hot HCN is decomposed upon contact with many At preseint the raw materials utlhzed to commercially Prometal substances, those parts of the equipment with which duce thls compound are natural gas or pelroleum. Prod' the hot HCN comes into contact should be constructed of ucts. Exemplary processes are the catalytic reaction of nommetals (cg ceramics) tf 2 alr i i ii g g g2: i gz The following example illustrates a specific way in mac o ammonia W1 .lqul y wear which the process of the present invention has been carthese hydrocarbon raw materials are comparatlvely reasried onably P at E they are bemg rapidly depleted 1593 grams of minus 300 mesh bituminous coal were Accordmgly, substitutlon of the abundant and cheap raw P1 a c e d in a Vessel and the vessel ressurized with terial coal for h drocarbon in the roduction of hyp g b d mercial-grade NH at 10 p.s.1.g. for a penod of tlme to gf 6 3 e i f i uantifes of enable 41 grams of NH, to be adsorbed thereon. Amh ave l lscovgre r :2 b as: mllnolm moniated coal was then charged to a hopper above a vertiy Ogen y 6 e p o y c g a cal ceramic reactor tube, and maintained in the hopper ated coal w1th ammonla at elevated temperatures. In comunder an ammonia atmosphere The coal was then fed Panson Wlth reaptmg the aIPmOma Wlth raw (unammom' downwardly through the reactor tube at a rate of 180 ated) coal, the increased yields produced by our process grams per hour (equivalent to a rate of about 50 pounds are c9mpletely unexpefzted' of coal per hour per square feet of cross-sectional tube It IS therefore an oblect of the Present .lnventlon to proarea), while the tube was maintained at a temperature of vlde a process for making hydrogen cyanide a chtap 1250 C. by means of electrical resistance heaters. Amand abundant l maltenal' A .further object ls to provide 45 monia was fed to the reactor tube at a rate of 1.0 ft. hr. a prqcess for f a l yield of HCN produced by Helium was used as a carrier gas. Product gases were reactmg l wlth ammoma' washed first with dilute H then water-washed to form Other ob ects and advantages Wlll. be obvious from a an HCN Solution feta-116d deSEglpu-on of the invcnnon appeanng in the fol- To compare the reaction of ammonia with ammoniated owing spec1 cation. 50

In the process of the present invention, coal, preferably and g i coal 131mahty of dlfferent coals in comminuted form, is enclosed in a vessel which is then unammomate an f m fomb were fed down pressurized (e.g., to 10-50 p.s.i.g.) with NH so that the wardly, o r y with helmm, through the reactor coal adsorbs about 0.01 pound or more of NH per pound dfiscflbed 1n the Precedmg p The tube was of coal. Thereafter, the ammoniated coal is brought into a n a at a p rature of 1250 C. Table I shows contact with ammonia gas in a heating zone wherein the the results of these tests.

TABLE I Oannel coal Anthracite coal Bituminous (h.v.a.) coal Unammoniated Ammoniated Unammoniatcd Ammoniated Unammoniated Ammoniated Coal teed, gJhr 115 -180 170-180 NH; employed for adsorption, ita /hr. 17 30 30 NHs gas flow to reactor, ttJ/hr 1. 00 83 1. 10 80 1. 15 80 Total NHa employed, ttfi/hr 1. 00 1.00 1. 10 1. 10 1. 15 1. 10 Helium carrier gas, itfl/hr 2. 07 2. 04 1. 02 l. 05 l. 01 Percent HON in product gas 9. 5 10. 9 1 6 8. 8 10. 9 HCN, fH/lb. coal 1. 24 1. 72 007 048 1. 30 1. 56 HCN, rte/n. total NH; feed.. 32 .44 004 017 43 57 Adsorbed on coal by pressurizing coal-containing vessel to I10 p.s.i.g. with ammonia gas. As pressure inside of the vessel dropped ofi (due to adsorption of ammonia on coal surface), vessel was repressurized to 50 p.s.i.g. This procedure was repeated until pressure inside the vessel remained constant, indicating no further adsorption of ammonia. Before the coal was transferred to the feeder-hopper ot the reactor tube, the ammonia pressure was reduced to atmospheric. During adsorption, the cannel coal adsorbed an amount; of ammonia equal to 3.2 percent of the coals weight, while the anthracite and bituminous coals each adsorbed ammonia equal to 3.6 percent of their weight.

9 Wet analytical method of analysis, carrier gas-free basis.

As can be seen from the Table I, when the coal is ammoniated, a marked increase in the amount of HCN produced per total amount of NH employed occurs. This increase ranges from over 32% for bituminous coal to over 300% for anthracite coal.

Considering the fact that coal presently costs cent per pound compared to 1 cent to 1% cents per pound for the hydrocarbon raw materials presently used to produce HCN, the process of the present invention ofiers a new, economical way to produce this valuable chemical.

While the particular process herein described is well adapted to carry out the objects of the present invention, it is to be understood that various modifications and changes may be made all coming within the scope of the following claims.

What is claimed is:

1. A process for producing HCN from coal and ammonia comprising a (a) ammoniating said coal under pressure until at least about 0.01 pound of ammonia per pound of coal is adsorbed; and

(b) reacting said ammoniated coal with ammonia gas at a temperature of from about 1000" C. to about 1300 C. to form HCN-containing product gas.

2. The process of claim 1 further comprising separating HCN from said product gas.

3. The process of claim 1 wherein said coal is bituminous coal.

4. The process of claim 1 wherein said reaction step comprises passing dispersed, particulate ammoniated coal through a heating zone containing said ammonia gas.

5. The process of claim 4 wherein said particulate coal is minus 300 mesh and said heating zone temperature is about 1250 C.

6. The process of claim 4 further comprising injecting an inert gas into said heating zone to carry out said product gas.

References Cited UNITED STATES PATENTS 2,671,015 3/1954 Morley 23210 FOREIGN PATENTS 854,268 11/ 1960 Great Britain.

OSCAR R. VERTIZ, Primary Examiner HOKE S. MILLER, Assistant Examiner US. Cl. X.R. 

